Merge pull request #37 from JosiahParry/explode

 explode lines functio

Author: JosiahParry

NAMESPACE

@@ -37,6 +37,7 @@ export(distance_haversine_pairwise)
 export(distance_vicenty_matrix)
 export(distance_vicenty_pairwise)
 export(expand_geoms)
+export(explode_lines)
 export(extreme_coords)
 export(flatten_geoms)
 export(frechet_distance)

NEWS.md

@@ -1,5 +1,6 @@
 # rsgeo (unreleased)
 
+* `explode_lines()` will expand an `rs_LINESTRING` or `rs_MULTILINESTRING` into their component segments
 * Adds `line_segmentize_haversine()` to segment LineStrings in geographic space.
 * Adds `geom_line()` to construct a straight line geometry between two point vectors.
 * Adds `coord_first()`, `coord_last()`, `coord_n()`, and `n_coords()` functions for working with coordinates of geometries. 

R/explode.R

@@ -0,0 +1,27 @@
+#' Explode Lines
+#'
+#' Given a LineString or MultiLineString, expand the geometry into each and
+#' every component Line.
+#'
+#' @param x an object of class `rs_LINESTRING` or `rs_MULTILINESTRING`
+#' @details
+#' A `LineString` is composed of one or more `Line`s. A Line is a connected
+#' by a start and end coordinate only.
+#'
+#' @export
+#' @returns an object of class `rs_LINESTRING`
+#' @examples
+#' x <- geom_linestring(1:10, 10:1)
+#' length(x)
+#' explode_lines(x)
+explode_lines <- function(x) {
+  if (rlang::inherits_any(x, "rs_LINESTRING")) {
+    res <- explode_linestrings_(x)
+  } else if (rlang::inherits_any(x, "rs_MULTILINESTRING")) {
+    res <- explode_multilinestrings_(x)
+  } else {
+    cli::cli_abort("{.arg x} must be of class {.cls rs_LINESTRING} or {.cls rs_MULTILINESTRING")
+  }
+
+  res
+}

R/extendr-wrappers.R

@@ -693,5 +693,9 @@ combine_polygons <- function(x) .Call(wrap__combine_polygons, x)
 
 combine_multipolygons <- function(x) .Call(wrap__combine_multipolygons, x)
 
+explode_linestrings_ <- function(x) .Call(wrap__explode_linestrings_, x)
+
+explode_multilinestrings_ <- function(x) .Call(wrap__explode_multilinestrings_, x)
+
 
 # nolint end